The Department of Energy (DOE) on Wednesday told workers that a hack in late July disclosed personal data, such as the identities and Social Security numbers of current and past employees, and around 14,000 individuals may have been affected.

According to information obtained by the Wall Street Journal, the agency said “No classified data was targeted or compromised.” The department added that they’re acting with federal law enforcement to determine more about the incident.

A undisclosed individual familiar with the matter told the Journal that hackers were able to gain access to a human resources system that included information like payroll data.

This isn’t the first time, back in February the DOE was targeted and successfully breached in February of this year, again, putting it’s employees at risk.